Combination lamp and heater



May 11, 1954 L. L. SALTON COMBINATION LAMP AND HEATER Filed Jan. 2, 1951 INVENTOR,

LEW/.5 L SAL-real Patented May 11, 1954 UNITED STATES PATNT OFFICE COMBINATION LAMP AND HEATER Lewis L. Salton, New York, N. Y.

A plication January 2, 1951, Serial No. 204,025

6 Claims. (01. 219-19) This invention deals with a novel combination lamp and heater, in particular with one involving a fluorescent lamp and a radiant glass space heater.

Fluorescent lamps as well as radiant space heaters, particularly radiant glass space heaters, are Well known and widely used because of their many advantages.

Fluorescent lamps are generally manufactured in the form of glass tubes which are usually straight, coated on the inside with phosphors, and closed by ends to which appropriate electrodes are fastened. The inside of the tube is filled with a trace of argon and with mercury vapor whose pressure is controlled by the presence of a small amount of liquid mercury in the tube. The electric potential applied at the electrodes causes the establishment of an electric discharge through the mercury vapor along the length of the tube which emits ultraviolet radiation which is, in turn, transformed by the phosphors into visible light. The main advantages of fluorescent lamps are their high conversion efficiency and the low intensity of light per unit surface, which results in low glare and uniform lighting.

An important limitation in the use of fluorescent lamps is that they are quite temperature sensitive. A rise of temperature to only 120 being sufficient to reduce the light produced by 40%. This limitation is particularly important when an attempt is made to utilize a fluorescent lamp near any type of space heater and accounts for the fact that while space heaters have been often combined with incandescent lamps they have not been used with fluorescent ones. Thus, for example, it has been found that when the ceiling of a room is paneled with radiant heaters operated so as to maintain the temperature of the room at a comfortable level, the operation of fluorescent lamps suspended from that ceiling is greatly impaired. This effect of temperature upon fluorescent tubes is apparently due to an increase in the pressure of mercury vapor within the tube as the droplet of liquid mercury becomes heated.

Radiant space heaters depend primarily on radiation of heat energy rather than on its conduction. They generally use relatively large surfaces of moderately high temperature and preferably having high absorptive (and therefore emissive) power for heat radiation. Radiant glass heaters are usually formed by a tempered glass plate, one side of which is almost completely covered by a winding thin ribbon of sprayed-on metal, generally aluminum, such 2 as described for example, in U. S. Patent 2,119,680 to B. Long. At the two ends of this ribbon are attached electrodes, which are connected to a source of current. When the current flows, the ribbon is heated and most of its heat is transmitted to the glass and then radiated out by this glass, because glass has a higher emissivity for heat radiation (infrared) than the metallic surface. A considerable amount of heat is, nevertheless, radiated by the metallic surface of the space heater and some is transferred to the surrounding air by conduction.

The objects of the present invention comprise the provision of an improved lamp and an improved space heater. Another object is to provide improved means of heating and illuminating work spaces in shops and other buildings. A further object is to obtain improved lighting and heating by the proper combination of fluorescent lamp and radiant heater, and still another, is to avoid any deleterious effects of the heater upon the lamp. Still further objects will become apparent from the following specification.

According to this invention, radiant heaters, preferable of the glass type, are placed next to a horizontal fluorescent tube, so as to reflect the light of the lamp and to heat, by radiation, the illuminated area. An important feature of my invention is that an opening is provided between the lamp and the heater through which an ascending current of air can flow. This air current has the effect of cooling the fluorescent lamp and prevent any deleterious effects of the heat generated by the heater.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawing showing by way of example preferred embodiments of the inventive idea. In the drawings:

Figure 1 shows a perspective view of a combination lamp and heater according to this invention Figure 2 shows a side and partially cut-away view of the device of Figure l, and

Figure 3 shows the cross section of a workshop heated and illuminated according to this invention.

In Figure l, the fluorescent tubes 1 are supported by brackets 3 attached to the lamp body 5 which houses the required electrical accesseries: starter, ballast, phase shifter, etc. not shown. On both sides of the lamp, and spaced therefrom, are placed the glass radiant space heater plates 1 supported by frames 8. The heating element is a sinuous ribbon ll of aluminum, which covers the back side of the glass plates I.

The construction of this device is shown in more detail in Figure 2. The lamp body 5 is directly attached to two crossbars I3, one of which is shown. Crossbar I3 is in turn suspended by chains I5 from a suitable fixture such as the hook I! in a ceiling I9. Crossbar I3 also supports two symmetrically spaced bracket 2| which are each solidary with a lug 23 attached to plate 25. Plate 25 is in turn set in frame 9 which supports the glass plate I bearing the aluminum ribbon -II on its back face. Spacers 2? keep plate 1 firmly set in the frame 9.

Electric current is supplied to the ends of ribbon II by wires 29 and 3i which lead to cord 33 connected to switch 35. Switch 35 is also connected by cord 3I to the other space heater, and is connected to cord 39 which supplies the electric current, from a ceiling fixture M, to the whole assembly. Pull cord 43 operates switch 35.

An important point in the construction of the combination lamp and heater according to my invention, is that there is sufficient unobstructed space between, on one hand, lamp I and hous ing 5, and on the other hand, each heater I to allow sufficiently rapid upward fiow of air between them. I have found that a 750 watt heat ing panel, 4 feet long and a fluorescent lamp of approximately same length, can operate satisfactorily when the unobstructed passageway between frame 9 and housing 5 is a quarter of an inch wide, but for best results, I prefer to make this width about one inch and not over about 5 inches. The spacing giving the best result depends somewhat on the shape and size of the heater, its power rating and the angle at which it is inclined to the horizontal. It is a simple matter of experimentation to find a suitable spacing in each case.

Figure 3 shows a large building 5I housing a relatively small workspace such as the bench 53. To illuminate and heat this workspace only, I provide the combination lamp and space heater 55 such as described in detail above, placed immediately over the workspace, close enough to give the desired concentration of light and heat and not so close as to interfere with the free use of this workspace.

In the operation of my device, electric current is supplied through fixture 4| and cord 3?, energizing tubes I. The light emitted by these tubes proceeds in part directly downward where illumination is desired such as upon bench 53 in Fig ure 3. Some of it is reflected diffusely by housing 5, which is customarily white, and some of it strikes glass plate I, penetrates through it, since glass is transparent to visible light, and is refiected by the aluminum ribbon II which covers most of the back surface of plate 1. After passing again through plate I, this light proceeds in the downward direction, i. e., towards the space to be illuminated.

When it is desired to use my device also for heating purposes, switch 35 is operated to energize the aluminum ribbon I I which heats plate I to a temperature of the order of 300 F. and plate i, in turn, radiates heat mostly in the downward direction, for example, towards bench 53 in Figure 3. Some of the heat radiated by each plate I is absorbed and then re-radiated by the other (since glass is opaque for heat radiation) and is thus directed downward. The aluminum ribbon II radiates some heat in the opposite direction and this is largely wasted from the point of view of heating the downward area. To reduce this loss, plate 25, which faces ribbon I I, is preferably made highly reflective so as to return most of this radiation back and spacers 21 are not only electrically but also thermally insulating. The same result may be obtained by covering ribbon I I with a good heat insulator such as a layer of asbestos, magnesia, or the like.

A certain amount of the radiated heat is also absorbed by the fluorescent tubes I. This amount increases as the angle a formed by the plate decreases. The heat thus absorbed by tubes I tends to raise their temperature and thus reduce their efiiciency. This deleterious effect is, however, prevented by the construction of my device, as will be explained immediately below.

The air in the immediate vicinity of plates l and of frames 9 becomes heated by conduction so that its density decreases and it tends to rise. Due to the spacing of frames 9 from tubes I and housing 5, it can freely ascend. It is replaced by fresh air which in turn gets heated and ascends. In this way, a continuous primary ilow of air is produced along plates I, as shown by arrows 45. This air current is, of course, more pronounced the smaller the angle or. This primary flow of air entrains, of course, adjacent masses of air and produces a flow of air past tubes I and in between them as shown by arrows 4i and 46 respectively. The result of this entrained air flow is that the fluorescent tubes I are cooled and I have found that their temperature, while lighted, is in fact, lower when plates I are operating than when these plates are not operating as heaters. Hence the effect of the space heater when used according to this invention, in addition to its action as a reflector, is to increase the efliciency of the fluorescent lamp. In order to cool properly fluorescent tubes I, it is necessary that the passageway for the rising air be wide enough so that the air can rise freely and not so wide so that the secondary flow of air fails to extend to the fluorescent tube and does not cool it.

It will be also apparent that both heat and light are concentrated into essentially the same area downward and within direct reach of the lower surfaces of my lamp and heater. In this way, little energy is wasted in heating and illuminating large unutilized areas and spaces normally present in shops and similar buildings.

The angle 0c, formed by the planes of the space heaters with each other, may vary, depending on the size of the space which it is desired to illuminate and to heat. It may vary from 180 or almost horizontal when a large area is to be covered, to 60 or less when a narrow covered space is desired. I find, however, that an angle between about 120 and is best adapted for general purposes and gives the best distribution of light and heat.

While a slot formed by the frame of the radiant heater and the lamp housing is most effective in allowing the formation of the desirable air currents according to my invention, other forms of openings may be provided instead, as long as they are of sufficient size to allow the escape of the heated air and prevent deleterious effects of the heater upon the fluorescent tube.

The space heaters described in the preferred embodiment of this invention are plane. This shape is preferred because of its easy manufacture and general availability. It is clear, however, that other shapes such as, for example, concave or convex cylindrical sections may be used with straight fluorescent tubes and spheroidal heaters or the like are more suitable for use with circular fluorescent tubes. It will be also apparent to those skilled in the art, that the construction of the combination lamp and heater may be modified in many other ways without departing from the spirit of my invention.

I claim as my invention:

1. In combination a fluorescent tube, a housing supporting said tube, a crossbar attached to said housing, two glass radiant space heaters each having a heat radiating and light reflecting surface in a light reflecting position with respect to said tube, said heaters spaced from said tube and said housing by a passageway adapted to allow the flow of an air current between each of said heaters and said tube, and brackets attaching said heaters to said crossbar.

2. The combination of claim 1 wherein said plate glass space heaters form an angle between 180 and 60 degrees with each other.

3. The combination of claim 2 wherein said angle is between 120 and 90 degrees.

4. In combination a fluorescent tube, a housing supporting said tube, two glass radiant space heaters each having a heat radiating and light reflecting surface in a light reflecting position with respect to said tube, said heaters spaced from said tube and said housing by a passageway adapted to allow the flow of an air current between each of said heaters and said tube, and

means for maintaining said housing and said heaters thus spaced.

5. The combination of claim 4 wherein said passageway is adapted to allow said air current to be caused by the heating effect of said space heater.

6. The combination of claim 5 wherein said passageway is furthermore narrow enough so that said air current has a cooling efiect upon said tube.

References Cited in thefile of this patent UNITED STATES PATENTS Number Name Date Re. 17,637 Brown Apr. 8, 1930 2,072,205 I-Ialpern Mar. 2, 1937 2,119,680 Long June 7, 1938 2,260,803 Dewar Oct. 28, 1941 2,338,077 Scribner Dec. 28, 1943 2,358,081 Marick Sept. 12, 1944 2,359,021 Campbell et a1. Sept. 26-, 1944 2,431,520 Streich Nov. 25, 1947 2,447,498 Ellner Aug. 24, 1948 2,453,832 Dadson Nov. 6, 19 8 2,485,410 Pope Oct. 18, 1949 2,495,788 Trist Jan. 31, 1950 2,513,993 Burton July 4, 1950 2,561,341 Clark, Jr July 24, 1951 2,575,486 Brandeis Nov. 20, 1951 FOREIGN PATENTS Number Country Date 515,643 Great Britain Dec. 11, 1939 

